Multi Temp rest batch sparge.

I was thinking I can mash in how I regularly do (1.25 qts to 1 lbs of grain in my 40qt Coleman cooler) but at a protein rest temp for 20 minutes. Drain the wort and heat it up to a beta rest temp, add it back to the grain bed, and repeat for a alpha rest and so on.

Has anyone done this or should I just not worry about doing temp rests since I'm batch sparging?

one word for you: Decoction
When you drain the wort, heat it, and add it back to the grain you are actually doing a thin-Decoction . Problem is, while you are heating the wort, your grain is sitting dry(ish) and getting cold. Better option is to draw a portion of the mixture (grain and wort) boil it, and add it back in to raise the temperature of the whole thing. Google Decoction for exact details. I'd recommend using a decoction calculator to get the volumes right for your temp stops

Or just add boiling water to raise the temps.

Well the problem with just adding boiling water is that once I get to a sacc rest my grain will be sitting in more water than I want.

I'm familiar with the decoction process, but never tried it. I''ll have to google thin decoction but it sounds pretty straight forward.

Decoction is made out to be this big scary thing, but it's really very straight forward. Randy Mosher gives a good overview of it in his book.
Thin decoction = a decoction where you take just the water with as little grain as possible. You get less caramelization, but you also get less thermal mass, so it doesn't raise the temp as much.

But you generally don't want to do a thin decoction (mostly liquid) until you go to mash out temps! You want to pull a THICK decoction (mostly grain) to go to saccrification rest temps. It has to do with pH and conversion. If you pull the liquid out of the mash, and warm it up, you'll totally mess with the enzymes and the pH.

You can mash in at the protein rest temps, and immediately pull the decoction. Let the decoction rest for 15 minutes at saccrification rest temp, and then bring that to a boil for a couple of minutes and then add it back to the mash. That should give you about a 20 minute protein rest (try not to go any longer than that).

TheBrewAbides said:

Well the problem with just adding boiling water is that once I get to a sacc rest my grain will be sitting in more water than I want.

I'm familiar with the decoction process, but never tried it. I''ll have to google thin decoction but it sounds pretty straight forward.

Click to expand...

What difference does it make?
Or just do the protean rest with less water?
So when you add the water to raise the temp. You hit the desired grist water ratio? That's how I've done it.

Go to northerbrewer.com, brewingtv, look for the episode called decoction day (i think). Browsing from my phone or I'd find the link right now.

Great walk-through, its really pretty straight forward. I plan to use this next sat for a large mash where I don't have room in my tun for a mash out infusion.

Listen to Yooper, if you do the decoction boil the grains and don't pull a lot of thin wort with it, you want it thick. The reason is you're going to boil it and that will denature the enzymes which are primarily in the wort. So you would only boil a thin decoction after the sacch rest to go to mash out. I wouldn't also try to heat the wort to hit the next temp when using a cooler since you would need to heat the wort past the point of denaturing the enzymes to get to the next temp step you want when adding it back in, so that is not an option.

Decoction is your best bet if using a cooler. Outside of that using a kettle for mashing would allow you to apply direct heat to get to the next temp.


Rev.

The other thing you could do is mash in thick (1 quart/pound) for the protein rest and then do a second infusion (up to 1.75 quart/pound- 2quarts/pound total) for the saccrification rest. I've done it, and it's certainly possible in a 40 quart cooler.

Yooper said:

The other thing you could do is mash in thick (1 quart/pound) for the protein rest and then do a second infusion (up to 1.75 quart/pound- 2quarts/pound total) for the saccrification rest. I've done it, and it's certainly possible in a 40 quart cooler.

Click to expand...

That's what I just did yesterday, but I came in a bit thicker, like .88 quart per pound of grain (9lb bill 2 gallons water), then used a gallon of boiling water to move to the next temp rest... though I missed the temp by several degrees.

That would work well for a two rest mash or so but if there are more rest points it would really thin the mash.


Rev.

I've done a four step infusion mash in my cooler. I mashed in at about 1 qt /lb and finished several hours and four rests later at 2 qt/lb

It worked great for a Belgian golden strong. Although I do detect some DMS, but I think that is more of a function with the boil, and the 95% pilsner malt?? Anybody know on that?

Yooper said:

But you generally don't want to do a thin decoction (mostly liquid) until you go to mash out temps! You want to pull a THICK decoction (mostly grain) to go to saccrification rest temps. It has to do with pH and conversion. If you pull the liquid out of the mash, and warm it up, you'll totally mess with the enzymes and the pH.

You can mash in at the protein rest temps, and immediately pull the decoction. Let the decoction rest for 15 minutes at saccrification rest temp, and then bring that to a boil for a couple of minutes and then add it back to the mash. That should give you about a 20 minute protein rest (try not to go any longer than that).

Click to expand...

^^ what she said


Don't pull out just the wort and heat it up...that will not work out well.

Yooper said:

The other thing you could do is mash in thick (1 quart/pound) for the protein rest and then do a second infusion (up to 1.75 quart/pound- 2quarts/pound total) for the saccrification rest. I've done it, and it's certainly possible in a 40 quart cooler.

Click to expand...

That's what I was trying to say.

Okay great! Thanks for the advice everyone. :rockin: